"I've never smoked, I exercise every day, forget alcohol - it's bad for my reflux - I've been the same weight my whole adult life. How is this possible? Well, guess what - it's possible," Blume wrote at her site JudyBlume.com.
The surgery was performed on July 30, six weeks after her diagnosis, she wrote. "Anyway, this surgery went well, one night in the hospital, very little pain."
Blume said her husband, family and friends have been supportive and that she has relied on a "network of amazing women" to overcome her disease.
Books by the New Jersey native have dealt with everything from divorce to bullying. Over 80 million copies of Blume's books have been sold, according to her website.